1. Field of the Invention
The present invention relates to a helmet with a ventilating function, and a ventilating shutter device applicable to this helmet.
2. Description of the Related Art
When a helmet put on a rider of a motorcycle or the like receives a high wind pressure from the front in, for example, a high speed traveling, a wind passing around the helmet causes a negative pressure (turbulence) to occur at a lower rear portion of the helmet shell, which often leads to a phenomenon that draws the helmet rearward. This phenomenon imposes a great burden on the muscles of the neck of the rider.
To inhibit this phenomenon, there has been proposed a rear deflector (rearwardly-oriented visor) attached to a rear portion of a helmet (refer to U.S. Pat. No. 4,586,197). This rear deflector is secured to a rim of a lower rear portion of the helmet and extending upwardly and rearwardly to cover the lower rear portion of the helmet. The rear deflector allows the neck muscles of the helmet wearer to be most relaxed (mitigating the burden on the neck muscles) at each speed in a motorcycle traveling in which the wearer's head is inclined forwardly or rearwardly.
A helmet with a ventilating function is known which is provided with an outside air path on the outer periphery of the helmet for allowing outside air to be taken therein from the front and to be discharged rearward (refer to, for example, Japanese Examined Utility Model Publication No. HEI 1-29209). The outside air flow passing through the outside air path causes a negative pressure that sucks inside air remaining within the helmet, thereby achieving ventilation. The helmet with a ventilation function described in this publication is formed with an air outlet in a lower rear portion of the helmet shell which is in the form of a rearwardly protruding square pipe.
Though this helmet is not capable of regulating the air flow rate, there is known a helmet provided with a shutter device in, for example, an upper front portion of the helmet shell for achieving air flow regulation.
If an attempt is made to attach the conventional rear deflector to the aforementioned helmet with a ventilating function, the rear deflector is likely to interfere with the air outlet because of their overlapped location and, hence, the attempt may fail. In addition, because such a conventional helmet has the air outlet protruding from the lower rear portion of the helmet shell and does not have the rear deflector, turbulence is likely to be caused by an outside air flow along an outer surface of the helmet shell and an outgoing air flow from the air outlet. Such turbulence will work as an air resistance to the helmet.
As described above, there is known a helmet with both a ventilating function and a shutter device for regulating the air flow rate. Such a shutter device is often made small so as to avoid conspicuousness in outward appearance, resulting in a limited amount of air to be taken in the air path.
If a plurality of such shutter devices were provided on the helmet shell to increase the intake air amount, troublesome and costly assembling and mounting of each shutter device would become necessary in addition to cumbersome individual operations for these shutter devices.
In view of the foregoing, it is a first object of the present invention to provide a helmet having a ventilating function and a deflecting function that do not interfere with each other and that provide a unified appearance to avoid mar of the outward appearance of the helmet as a whole.
It is a second object of the present invention to provide a helmet having a ventilating function and a deflecting function that do not interfere with each other, while allowing a rearward outgoing air flow caused by the ventilating function to be smoothly released from the helmet shell thereby preventing the occurrence of air resistance attributable to the ventilating function.
It is a third object of the present invention to provide a helmet that effectively utilizes a rearward outgoing air flow caused by the ventilating function to enhance the deflecting function of a rear deflector, thereby enhancing the fitting stability of the helmet on a rider of a running motorcycle or bicycle.
It is a fourth object of the present invention to provide a ventilating shutter device that is applicable to a helmet having a ventilating function and a rear deflector, and that does not mar the overall outward appearance of the helmet.
It is a fifth object of the present invention to provide a ventilating shutter device that is applicable to a helmet with a ventilating function, that ensures a sufficient amount of intake outside air for ventilation without marring the outward appearance of the helmet, and that can be assembled, mounted and operated easily.